Heat sealing machine



Nov. 26, 1968 w. L. LANGEVIN 3,413,178

HEAT SEALING MACHINE Filed Oct. 19, 1965 3 Sheets-Sheet 1 I 96 5;; ;i m j 120 5 I H i {F5 h F'l 64-\ H1 M, ms

1968 w. L. LANGEVIN 3,413,178

HEAT SEALING MACHINE Filed Oct. 19. 1965 3 Sheets-Sheet 2 Nov. 26, 1968 w. L. LANGEVIN HEAT SEALING MACHINE 3 Sheets-Sheet 5 Filed Oct. 19, 1965 United States Patent Otfice 3,413,178 Patented Nov. 26, 1968 3,413,178 HEAT SEALING MACHINE Wilfred Louis Langevin, Beverly, Mass., assignor to Boston Machine Works Company, Lynn, Mass., a corporation of Massachusetts Filed Oct. 19, 1965, Ser. No. 498,064 3 Claims. (Cl. 156-545) ABSTRACT OF THE DISCLOSURE A machine for heating and pressing a sealing tape progressively on a seam of an article of wear, comprising a pair of rolls, one of which is driven, between which the seamed article passes,

a heated, wedge-shaped shoe movable to and from a position close to the nip of said rolls,

a jacket of insulation on said shoe,

a motor to drive one of the rolls,

automatic means for starting the motor when the shoe moves to the nip of the rolls and for stopping the motor when the shoe moves away.

This invention relates to a machine for applying a waterproof heat-activated tape to the seam of an object, such as an article of clothing, which is composed of two or more pieces of sheet material which have been stitched together. The machine is designed to apply heat as well as pressure at the point where the tape comes in contact with the seam so that the tape is welded to the article on top and on both sides of the seam, thus making the seam watertight. By way of example, the machine is described as applying vinyl tape to the seam of a boot made by stitching together two suitably shaped pieces of vinyl sheet or expanded vinyl with cloth backing. When pieces of such waterproof material are stitched together, the needle pierces the sheet material to make the stitches, and in so doing provides many small passages through which moisture can seep into the boot. To close these passages, a waterproof tape is applied to the seam to overlie it, the tape being heat welded to the boot on the sides and top of the seam.

It is an object of the invention to provide means by which the tape can be rapidly and accurately applied to overlie the seam and to be welded to the seamed article on the top and sides of the seam, thus making the seam watertight. A machine embodying the invention is illustrated on the drawings, of which FIGURE 1 is a front elevation of the machine;

FIGURE 2 is a partial side elevational view of the machine, as seen from the right in FIGURE 1;

FIGURE 3 is a partial elevational view of the machine as seen from the left in FIGURE 1;

FIGURE 4 is an elevational view of the heater shoe as indicated by the arrow 4 in FIGURE 3;

FIGURE 5 is a partial side elevation similar to the view in FIGURE 3 but lower down;

FIGURE 6 is a fragmentary end view of the two sheet pieces joined-by a seam;

FIGURE 7 is a fragmentary end view of the seamed pieces after the seam has been taped and reduced;

FIGURE 8 is a side elevation of the heater shoe and jacket with an upper seam guide attached;

FIGURE 9 is a bottom view of the same; and

FIGURE 10 is a small-scale outline of a typical seamed work-piece to be taped.

The machine illustrated on the drawings is a bench type machine and is mounted on a suitable table 20. The machine has a frame 22 which houses an electric motor 24 connected to a suitable source of power (not shown).

The motor is connected through speed-reducing connections with a drive shaft 30 on which is mounted the upper roll 32 of a pair of engaged rolls, the lower roll 34 being pressed against the upper roll by well-known adjustable means (not shown). As indicated in FIGURE 2 the motor 24 may be connected by a belt 36 to a slower turning Wheel 38 on a shaft 40. On this shaft is a pulley 42 connected by a belt 44 to a large wheel 46 on a shaft 48. A pinion 50 on this shaft meshes with a large gear wheel 52 on the drive shaft 30.

When the machine is in operation, the work and a heat-activated, waterproof tape are fed between them. One or both of the rolls has a circumferential groove to receive the seam of the work-piece. On the drawings the lower roll 34 has this groove 54 in its periphery which is preferably a rim of soft rubber or the like. The periphery of the upper roll 32 is of metal and is knurled. The tape T is drawn from a suitable supply such as a roll 56 mounted on a bracket 58. The tape passes through a guide 60 and through a second guide 64 which prevents the tape from working edgewise off the top roll 32, then through the nip of the rolls 32 and 34.

The lower roll 34 is idle and is rotatably mounted on the upper end of a post 66. The post also carries a lower seam guide 68 in a portion of the groove 54 near the nip of the rolls to assist in feeding the work-piece between the rolls so that the seam 70 will be centered under the tape as indicated in FIGURE 7, the margins of the tape being pressed firmly against the parts of the work-piece on either side of the seam 70. The post 66 is mounted at its lower end on a horizontal rock shaft 74 so that it can be rocked forward out of contact with the upper roll to facilitate the introduction of a work-piece between the rolls for the application of tape to the seam. This is done manually by means of a handle 76 mounted on the shaft 74 and projecting forward for convenient manipulation by the operator.

To make a seam watertight the tape is welded to the work-piece at the sides and on the top of the seam by the application of heat at the point where the tape first comes into contact with the work-piece. For this purpose a shoe 80 is arranged to swing down into contact with the tape and work-piece as they are about to enter the nip of the rolls 32 and 34. The shoe 80 is a block of a material that can be highly heated such, for example, as a metal or ceramic. An electric heating unit 82 is fitted into a bore which extends in from the forward end of the block. The rear end of the block, which faces the rolls, is beveled to form an acute dihedral angle having a sharp edge 84 which is notched at its middle as at 86 to accommodate the seam of a work-piece. An upper seam guide 88 is mounted under the shoe 80 as indicated in FIGURES 8 and 9 to cooperate with the lower seam guide 68 in steering the seam into proper contact with the tape T. The guide 88 consists of a plate 90 and a pair of cars 92 which extend toward the end 84 of the block and are inclined from each other to make an inverted channel over the lower guide 68.

The shoe 80 is shown in FIGURES 3 and 5 without the seam guide 88 and also without an insulating jacket 94 which is provided to conserve heat and to give partial protection to the operator from serious burns which would result from accidentally touching the highly heated shoe itself. The insulation to asbestos or the like in a sheet metal casing attached to rock arm 96 which also supports the shoe 80 itself. The plate 90 of the guide 88 is secured to the bottom of this casing. The rock arm 96 extends down from and is fixed on a rock shaft 98 which is journalled in the upper part of the frame 22. The shoe 80 is yieldingly held in the inoperative position illustrated in FIGURE 3 by a spring 100 attached at its upper end to the frame 22, the lower end of the spring pressing 3 on an arm 102 fixed to the rock shaft 98. The arm 102 extends beyond the shaft 98 and this extension carries a finger 104 arranged to close a microswitch 106 when the arm 102 is rocked clockwise against the pressure of the spring 100. This movement swings the shoe into operative position, as shown in FIGURE 5, 'in which the shaped end is adjacent to both rolls at the nip thereof. To accomplish this conveniently a third rock arm 108 is secured to the rock shaft 98 and is connected by a rod 110 or other means to a treadle 112. Depression of this treadle by the operator rocks the shaft 98 clockwise, thus swinging the shoe 80 into contact with the tape and work-piece where they join, also closing the microswitch 106. This activates the motor 24 to drive the top roll 32 which continues to rotate and to drive the lower roll by contact until the treadle is released, permitting the spring 100 to swing the shoe 80 away from the rolls 32 and 34 and to open the microswitch 106, stopping the motor 24.

The heating unit 82 is connected to the power source by another circuit the current in which is controlled by a rheostat 114 operated by a knob 116. A multi-wire cable 120 connects the microswitch 106 with the motor 24 and the heater unit 82 with the rheostat 114 through a branch cable 122. Both of these circuits include a main switch 124, a tell-tale light 118 being provided to glow when the main switch is on.

The machine is designed to tape the seams of vinyl rainwear including boots and coats. The heating current is first turned on. When the shoe 80 is sufficiently hot for the purpose, the post 66 is rocked forward to facilitate the placing of the start of the seam on the lower roll 34. The post is rocked back to its normal position and the treadle 112 is depressed. This swings the hot shoe 80 into contact with the tape and work-piece at the nip of the rolls and starts the motor 24. When the end of the seam is reached, the treadle is released, the shoe 4 swings back to inoperative position and the motor stops.

I claim: 5

1. A machine for welding thermoplastic tape to a workpiece, said machine comprising a frame, two mutually engaged rolls carried by said frame, means for guiding a thermoplastic tape between said rolls, a shoe comprising a metal block with a heating unit therein, means for connecting said heating unit to a source of electric power, one end of said block being shaped to form an acute dihedral angle, supporting means for said shoe operable to move said shoe to and from an operative position in which said shaped end of the block is adjacent to said rolls at the nip thereof, and power means for driving one of said rolls.

2. A machine as described in claim 1, said supporting means for the shoe including a spring arranged. to maintain said shoe yieldingly in its inoperative position, and operator-actuated means for moving said shoe into operative position.

3. A machine as described in claim 2, said power means comprising an electric circuit with a motor and a normally open switch connected therein, said support means for the shoe including a member arranged to close said switch as said shoe is being moved into operative position.

References Cited UNITED STATES PATENTS 2,625,287 1/1953 Holt et a1. 156-359 2,749,966 6/1956 Roetger -156--201 2,984,287 5/1961 Clason 156 581 XR 3,038,982 6/1962 Ludlow 156 -464 XR 3,194,715 7/1965 Gambin 156-583 EARL M. BERGERT, Primary Examiner.

M. L. KATZ, Assistant Examiner. 

